The present invention relates to control of disk drives in computer-type systems.
Essentially all types of modem computers are provided with systems of data storage (reading or/and writing information) on the base of disk drives. E. g., CD-ROM drive is the disk data storage device that has enjoyed the widest application in personal computers. Disk drives are very efficient data storage systems due to short time of hunting for written-dawn information and their high-reliability.
In all disk drives information pickup comes about through rotation of the disk containing coded information, the speed of reading being increased with the disk rotation rate. At the same time, high rotation rate is followed by objectionable acoustic vibrations and noise caused first of all by inevitable disk misbalance. E. g., it is just CD-ROM drive that proves to be, when in operation, the main source of noise and vibration in personal computer.
In contrast to, say, DC current fan motor, for which rotation rate may be modified from the outside by variation of power supplied to the motor, modern disk drive contains a built-in system (the drive controller) that controls over the disk rotation rate (see FIG. 1 and corresponding description below). E. g., in modem CD drive provided with a step motor, the drive controller generates electric pulses supplied to the motor and is able to change the pulse repetition rate determining the motor rotation rate. To change the motor rotation rate from the outside (from the PC motherboard)xe2x80x94to set it to motion, to stop, etc.xe2x80x94it is necessary to send a corresponding command to the drive controller via the PC system bus. The list of commands is specified by the drive manufacturer, and depends of the drive type. Generally, in modem PCs such commands are used to stop a disk drive or to set it to rotation at the maximal available rate specified by the drive manufacturer. Typically (e.g., for CD drives) the manufacturers give not the maximal rotating rate of the disk, but (proportional to it) maximal rate of reading/writing information from/to the disk.
It should be noted that for typical applications the speed of information reading from (writing to) disk is of no importance. E. g., for most of modern programs 12xc3x97 (i.e., approximately 12xc3x97150 Kbyte/sec) CD-ROM rate would be quite sufficient, while the most commonly employed today types of the drive afford the rate of 50xc3x97.
The present invention employs simple and novel methods and apparatus for overcoming the disadvantages of high level of noise and vibration generated by CD-ROM drive (and other types of disk drives) in personal computer. The principle of the approach consists in control over the disk drive rotation rate, manual or automatic, to set it to minimal value providing a sufficient data exchange rate for the given logical operation mode.
In accordance with the principles of this invention, the noise generated by at least one disk drive in personal computer is a source of noise and vibration caused by disk rotation, the noise and vibration being a is found to be a non-decreasing function of the rotational rate of the drive motor. In order to reduce the noise, it is necessary to reduce this rotational rate. To this end, a program or/and hardware module is installed to the computer to control over the disk drive rotation rate. The module generates specific command coming to the drive micro-controller to set its rate to a certain value, the command being taken from a data file, which contains for said disk drive a table that lists for each rotation rate of the drive a command to set the drive to the rate. In manual operation regime the rotation rate value is chosen by PC user via user""s interface either directly, or by specifying a logical operation mode of the drive (xe2x80x9claser record-playerxe2x80x9d, etc.). In automatic mode, the drive rotation rate is determined algorithmically by step-wise decreasing the rate from the maximal value (assigned by the drive manufacturer) to the rate that yields an allowable noise level. In the latter mode, the apparatus incorporates additionally a noise level sensor (e.g., a microphone), and the data file also specifies a maximum allowable noise level.